Deep Diving Gas Planning

[DaleC]

There are about a hundred threads on SB about mounting a pony in which the pros and cons of ech method are endlessly debated. Do a search and you will have plenty of reading material.
Try PMing Hawkwood on the board here. I believe he lives on Lake Chapparal.

 

[lowtech]

Wow. To start... A pony bottle is for anyone who would like additional redundant air source in the event of a failure. This is directed at response posted about pony only being for solo divers.. I.e that's ridiculous.

To the OP. You did protect yourself from the spare air doubles argument but let's discuss the ... Only 19 dives thinking of slinging a pony as well as an al80 to a float all while incurring no mandatory deco argument. Or let's not.

My apologies, I didn't mean to come off as "pony bottles are only for solo divers".
I was trying to indicate *my* thought process on it's utility on the dive(s) the OP was indicating.

I think a pony bottle is a great resource in the advent of loosing one's gas supply, and should be looked at as a tool to abort this type of dive successfully.

When I read OP what caught my eye was reserve gas being strung on floats and slung on the diver. On my end I could not get a sense of a gas plan, and I think that's what the OP was looking for help with. I was merely trying to convey, what my thoughts would be as a diver with similar experience.

 

[Garth]

OK, who's doing body recovery for this chap?

Seriously, get some experience with a mentor before trying all this nonsense.

I have to agree dude. Little harsh but true.
The other important comment listed by other people you should hear again is " you don't fall into an deco obligation, you put yourself into deco."
The advice is good whether you want to hear it or not ... Find a mentor.

 

[ianr33]

You won't have to worry about low oxygen levels at depth. I've never heard that narcosis is worse at altitude, but the depth and cold water can ring your bell.

Agreed.

Narcosis at a given depth should be less on an altitude dive as the pN2 will be less. (MOD is slightly greater as well)

The dominant factor will be the cold and dark though. As others have said, 130 feet in a cold dark lake is NOT the same as 130 in the Caribbean

 

[nadwidny]

I fully agree, the problem was I was assuming like minniwanka where most of the dives are advanced dives, 60 to 80 feet or lower.

You will need a shovel to get deeper than 80 feet in Minny.

On the question of the pony, I've been pondering the best way to carry it, sling it or just bracket mount to the back of my main tank. Advantage of slinging it is I can hand it off to my buddy if needed. I'm thinking AL40 (between 100 and 200$) + 1st stage ($100) + second stage ($100) + spg ($50) so 450 might be just the kind of protection from gear failure (not bad gas planning) I need.

Thoughts for the area?

A slung Al40 is the best bet as you can use it if you go down the technical path. If you want to bracket mount it you might as well just go with doubles in the first place.

 

[Paleface]

Hi Oldfng, I am a new diver with about 40 dives all of them have been in cold water quarries and mid atlantic. I will assume your 4 deg is c not f. When I dive down to 42*F my lips get numb and it can give me a bad headache and wow try flooding your mask one time.This is certainly something you should try little by little. Keith

 

[Superlyte27]

I would also personally be *highly* reluctant to count a tank strapped to my float into my emergency gas plan. If you do so and surface to find that it's somehow come unclipped and no longer there,

I actually saw an example of this the past weekend in cave country. A deco bottle was tied off (not by me) and someone untied it and the bottle was aloud to drift. Thankfully not far, but certainly not where it was tied. Granted it's location might not have been the greatest anyway.

But, if you count on a bottle to be there and it's not there how screwed are you?

 

[Garth]

OP: why are you so concerned with having extra tanks available and weights at you safety stop? Have you had to use them at all in your training dives? It sounds like something a boat would do to protect it's ass from poorly skilled divers that didnt plan well.
Since you are here to proclaim your plan I would assume you wouldn't need al80' dangling from a float or lift bag...
Have you determined your SAC rate yet?

 

[OldFNG]

OP: why are you so concerned with having extra tanks available and weights at you safety stop? Have you had to use them at all in your training dives? It sounds like something a boat would do to protect it's ass from poorly skilled divers that didnt plan well.
Since you are here to proclaim your plan I would assume you wouldn't need al80' dangling from a float or lift bag...
Have you determined your SAC rate yet?

I have for warm water, I haven't yet for cold water in a dry suit. My sole concern with extra gas and weights at my saftey stop is craps going to happen, I am assuming my gas consumption will go up dramatically in these conditions until I get into my groove.

After thinking about this over night, the boat probably was just protecting its ass from poorly skilled divers that didn't plan. Not once during my dives did I need to use the tanks and weights, however I just like planning for contingencies and then throwing in more insurance just in case crap goes south. So in order of preference my plan was:

1) Reserve Gas on Back
2) Reserve Gas in pony
3) Reserve gas off buddy
4) Reserve gas at safety stop

Since #4 isn't done here, I'm still going with #1 through 3

 

[UCFKnightDiver]

I have for warm water, I haven't yet for cold water in a dry suit. My sole concern with extra gas and weights at my saftey stop is craps going to happen, I am assuming my gas consumption will go up dramatically in these conditions until I get into my groove.

After thinking about this over night, the boat probably was just protecting its ass from poorly skilled divers that didn't plan. Not once during my dives did I need to use the tanks and weights, however I just like planning for contingencies and then throwing in more insurance just in case crap goes south. So in order of preference my plan was:

1) Reserve Gas on Back
2) Reserve Gas in pony
3) Reserve gas off buddy
4) Reserve gas at safety stop

Since #4 isn't done here, I'm still going with #1 through 3

I'm curious, could you please explain how you calculate your gas and plan your dive on a dive such as one you described previously? I too think you have way too few dives to do dives such at these.

P.S. The PADI Deep Diver specialty is usually crap and doesn't give you near the knowledge or skills needed to safely dive deep in my opinion.